Doctor of Philosophy / A large number of neuroendocrine studies indicate a possible relationship between the Hypothalamo-Pituitary-Gonadal (HPG) axis and major depressive illness in men. This observation is not surprising, considering the similarities between the symptom profiles of depression and hypogonadism. However, owing to the strong likelihood that a number of other demographic, clinical and treatment covariates may potentially obscure a possible relationship between HPG and depression, studies in this area have produced somewhat inconsistent results. The main objective of the present study was to investigate the relationship between depression and HPG hormone levels in a population of hospitalised men. Another objective was to examine the relationship of a number of demographic, behavioural, clinical and treatment variables with HPG hormone levels and depression. METHOD: Serum hormones of the HPG axis (Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH), Free Testosterone (free T), Total Testosterone (total T) and Sex Hormone Binding Globulin (SHBG)) were compared between fifty-two male patients with Major Depressive Disorder (mean age = 42.04; SD = 14.1) and twenty-five male patients with other psychiatric conditions (mean age = 40.72; SD = 13.8) on admission into hospital. In addition, to elucidate the possible relationship between clinical outcome of depression and gonadal function, HPG parameters were measured in patients with depression 3 to 6 months following discharge. Based on their HDRS (Hamilton Depression Rating Scale) score, patients were categorised as remitters and non-remitters. Demographic, behavioral, clinical and treatment variables were also examined as possible correlates of hormone levels. RESULTS: Comparison between patients with depression and patients with other diagnoses indicated a significantly lower free T and total T in patients with depression. There were no differences in other hormone parameters between the two diagnostic groups. Correlational analyses indicated significant negative relationships between free T and total T and severity as well as duration of depression. Age was inversely correlated to both free T and total T, whereas BMI was negatively correlated with Total T and SHBG. There was a positive relationship between Total T as well as Free T and measures of sexual dysfunction. While no difference in hormone parameters was observed as a function of psychotic features, patients with melancholic features exhibited significantly lower levels of free T and total T compared to patients with no melancholic features. In the multiple regression analyses, age, duration and severity of depression were the strongest predictors of both free and total T. In separate regression analyses somatic features, over and above other features of depression were found to account most in the variability in free T and total T. Longitudinal analysis revealed significantly higher free T and total T levels on follow-up compared to baseline in the patients who remitted. There was no significant change in any of the hormones studies in the non-remitting group. CONCLUSION: The main findings of the present study support previous results that both total and free testosterone levels are lower during depression and that concentrations of free T and total T parallel changes in severity of depressive symptomatology. Further investigations into the mechanism for this observation, and perhaps examinations of testosterone supplementation for treatment of depression are in order.
| Identifer | oai:union.ndltd.org:ADTP/283310 |
| Date | January 2006 |
| Creators | Brdaroska, Bilyana |
| Source Sets | Australiasian Digital Theses Program |
| Language | en_AU |
| Detected Language | English |
| Rights | The author retains copyright of this thesis., http://www.library.usyd.edu.au/copyright.html |
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